I get Dan’s point. Trump sitting in jail would rally the troops and paint him as a political prisoner. It would also disrupt things at the Fulton County Jail with the Secret Service taking over a large portion of the cell block, which would increase overcrowding and draw protests from the left.
But as Jon said, there is no way Trump would be able to handle life in jail. He’d be wearing the jail clothes and not a fancy suit. He’d be alone in a cell and couldn’t post on social media or watch whatever right wing channel he favors now.
I also suspect the Secret Service would tell him he had to post bail just for security purposes.